Gravenberch's talent was obvious during his first season at Liverpool under Klopp but he had still looked a little lost at times. After the Zubimendi U-turn, though, Slot found the perfect position for the Netherlands international in front of the back four.
However, Gravenberch adapted better - and quicker - to the change than even Slot imagined. Indeed, the player's father knew after the second match of the 2024-25 season, against Brentford, that everything was about to change for his son.
"One minute before the game ended, Arne took Ryan off so he could get the applause," Gravenberch senior told ESPN. "I was in the stands and the whole stadium stood up and applauded.
"I just broke down because I thought: 'They're doing this for my boy.' That was the moment where I thought: 'This is it.'" And it was.
As well as winning possession more times (193) in the Premier League last season than any other Liverpool player, and making more interceptions (60) than any other midfielder, Gravenberch also demonstrated a remarkable ability to break the opposition press that Slot attributes to a unique gift for gliding past opponents.
"This is a special quality Ryan has, that he can turn away from his man," Slot enthused. "He is one of the few holding midfielders, pivots, that can create an overload with a dribble.
"Mostly, these players pass a lot, and Ryan is good in passing as well. But to create an overload with a dribble, you don't see this many times from a No.6."
Slot really is right, then, when he says that Gravenberch is "unique". There are few better midfielders in the world right now.
Pedri and Vitinha are both absolutely outstanding while Rodri remains the standard by which all others are judged - but there isn't another No.6 in the game has Gravenberch's particular set of skills and the crazy thing is that, at 23, he's only going to get better.
We're already seeing an improvement, in fact.